In semiconductor industry, integrated circuits (ICs) are formed on a semiconductor substrate and are saw to IC chips. Each IC chip is further attached (such as by bonding) to a circuit board, such as a printed circuit board in electric products. In previous technologies, various bonding pads of the chip are connected to the circuit board through wire bonding. In advanced technologies, a circuit chip is flipped and directly bonded to the circuit board for reduced cost. In this technology, a redistribution layer of conductive metal lines is formed on the chip to reroute bond connections from the edge to the center of the chip. The existing structure of the redistribution layer and the corresponding method cause either metal filling issue, which further causes passivation defect. Therefore, the present disclosure provides a redistribution layer structure and a method making the same to address the above issues.